Using DA 7900 band on front derailleur with braze on frame

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londoncommuter
Posts: 958
Joined: Tue Jan 27, 2009 20:26 pm

Using DA 7900 band on front derailleur with braze on frame

Postby londoncommuter » Tue Nov 06, 2012 12:12 pm

Does anyone know if it's possible to use a band-on 7900 FD on a braze-on frame? If it's possible, do you need to buy any extra bits to make it work?

I've seen comments about buying adaptors to go from braze-on to band-on so it makes me think it could be done.

There are details here but it's not that obvious to me:

http://media.canyon.com/download/manual ... 900_EN.pdf

Many thanks for any help offered.

andyk19
Posts: 161
Joined: Sat Apr 14, 2012 09:56 am

Re: Using DA 7900 band on front derailleur with braze on fra

Postby andyk19 » Tue Nov 06, 2012 12:54 pm

I would expect it wouldn't work as to use a band on front mech the seattube needs to be a constant width of the correct diameter for a band on mech (28.6mm, 31.8mm or 34.9mm). Many frames intended for a braze on mech will not have a seattube of those dimensions, many aren't even completely round, so you just won't be able to get a mech on correctly.
Also the braze on mount usually will sit where you want to put the band meaning that you wont be able to get the clamp around the frame.
Lastly I'd be careful if it is a carbon frame as if it is designed for a braze on mech the seattube walls may not be thick enough to take the clamping force. I'm not saying this would be the case, but it's best not to find out.

londoncommuter
Posts: 958
Joined: Tue Jan 27, 2009 20:26 pm

Re: Using DA 7900 band on front derailleur with braze on fra

Postby londoncommuter » Tue Nov 06, 2012 13:12 pm

andyk19 thanks.

I was hoping to remove the band-on bit and it would then it would magically work as a braze-on derailleur. Looking more at pictures of them I don't think it's possible.

BuckMulligan
Posts: 655
Joined: Sat Mar 12, 2011 20:18 pm

Re: Using DA 7900 band on front derailleur with braze on fra

Postby BuckMulligan » Wed Nov 07, 2012 12:39 pm

There are adaptors to make a braze-on mech into a band-on, i.e. a band clamp with a braze-on mount at the front. I really can't see it being possible going the other way; unless your 'band-on' mech is actually a braze-on with an adaptor then it won't be possible.


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